By studying data from the Framingham Heart Study (FHS), researchers from Boston University School of Medicine identified combinations of factors that were linked to an increased risk of dementia in older age.

The findings were published in the Journal of Alzheimer's Disease on May 8. The researchers stated they wanted to focus on modifiable risk factors which could help people plan the right interventions to effectively reduce their chances of developing the disease.

"We wanted to identify information that any physician or even non-physician has easy access to in determining potential increased future risk for dementia," said corresponding author Dr. Rhoda Au, professor of anatomy and neurobiology. Here are four of the life-related risk factors:

1. Age

Age is considered the most significant risk factors for this disease which rarely affects those under the age of 60. According to estimations by the Alzheimer's Association, one in three senior Americans dies with some form of dementia.

On a related note, a 2018 study from the Yale School of Public Health found that attitudes toward aging may also play an important role. After analyzing a cohort of 4,765 older Americans, the research found that those with positive age beliefs were 49.8 percent less likely to develop dementia than those with negative age beliefs.

2. BMI

Conflicting results have emerged from studies that examined body mass index (BMI) as a possible risk factor for dementia. While some suggest that lower BMI is the culprit, others have rejected this and found that a high BMI is what seems to be linked to an increased risk.

A 2017 review concluded that a majority of literature has provided evidence that obesity in mid-life was linked to a higher risk of dementia, while the association of the disease with being underweight remained inconsistent at best. It has been noted that excess body weight in mid-life could contribute to neurodegenerative damage, which may increase the chances of dementia.

"While there are currently no sure-fire ways to prevent dementia, current best evidence suggests that maintaining a healthy weight is a key way to keep our brains healthy," said Dr. Rosa Sancho, Head of Research at Alzheimer’s Research UK.

3. Marital status

The new study also found that the marital status of "widowed" was strongly associated with dementia. Previously, research has provided similar findings on older adults who are single or have lost a spouse.

Andrew Sommerlad, a psychiatrist at the University College London in England, stated that the lower risk was not a direct effect of wearing a wedding ring. He referred to something known as "a possible protective effect" linked to various lifestyle factors that may accompany marriage, such as lower chances of loneliness, a generally healthier lifestyle, having more social stimulation, etc.

4. Sleep

Those who experienced less sleep at mid-life may also be more likely to develop dementia. A study from 2017 found that people took longer than 90 minutes to enter REM (the fifth stage of sleep) were at high risk for developing dementia.

Though it is known that poor sleep can contribute to cognitive decline, the mechanisms underlying this association have not been firmly established. What is clear is that treating sleep disorders, establishing a routine, and learning to prioritize good quality of sleep is highly recommended earlier in life to avoid short-term and long-term health problems.